The road measures 55.60 miles long and would take a car obeying speed limits 1 hours and 38 minutes to travel its length.
The A21 is a A Road and is located in the Zone 2 Highways Region.
This is a true long-distance route, journeying through numerous towns like Catford, Lewisham, BROMLEY, Farnborough, ORPINGTON, Pratts Bottom, Halstead, Chipstead, SEVENOAKS, Ide Hill, Weald, Hildenborough, Leigh, TONBRIDGE, Southborough, Tudeley, Pembury, TUNBRIDGE WELLS, Matfield, Lamberhurst, Flimwell, Hurst Green, ROBERTSBRIDGE, Salehurst, Mountfield, Whatlington, Sedlescombe, HASTINGS, and ST. LEONARDS-ON-SEA.
The road passes through several counties, including Greater London, Kent, and East Sussex.